System.Xml.DocumentXmlWriter.AddAttribute C# (CSharp) Méthode

        void AddAttribute(XmlAttribute attr, XmlNode parent) {
            if (parent == null) {
                fragment.Add(attr);
            }
            else {
                XmlElement elem = parent as XmlElement; 
                if (elem == null) {
                    throw new InvalidOperationException();
                }
                elem.Attributes.Append(attr);
            }
        }